Change style of header

please show how to change the style of the header and/or add this functionality in a feature release.

<!-- WP Attachments -->
        <div style="width:100%;margin:10px 0 10px 0;">
            <h3>Attachments</h3>

right now i also cannot simply add a custom css style because this plugin does not use any defined class, only the default html tag <h3>

i want to change the style for the header, simply reduzing the size for example

/edit
i changed in the source this
<h3>' . $orderby_html . get_option('wpatt_option_localization') . '</h3>
to
<span style="font-weight:bold;">' . $orderby_html . get_option('wpatt_option_localization') . '</span>

for my needs, i hope there will be an option in the settings in a feature release just like we can change the style now for the files and i will not loose this change without noticing in a distant future.